Description (taken from application): At the first renewal of the DERC in 1984, a new Cell Biology Subcore was developed to address the needs of a number of DERC investigators using or planning to use morphological techniques in their work. This new component was originally approved and funded to provide a wide variety of services under the title of "Receptor Localization" and included light and electron microscopy, immunocytochemistry, autoradiography, and the subroutines generally associated with these methods. At the 1992 renewal, the emphasis of the Core shifted to accommodate the significant number of DERC members who were interested in integrating the technique of in situ hybridization into their research. Hence, the Core came to be known as the "In Situ Hybridization Core," although the previously offered morphological services were still available and used. As documented in this renewal, a number of DERC investigators have availed themselves of the services of this Core. In the current renewal, we plan to again respond to the evolving needs of the research community and provide two new services based on morphological techniques: 1) confocal microscopy and 2) morphological analysis of transgenic mice and rats, both pre- and postnatal. It should be stressed that both of these new services do not represent a major departure from already existing Core functions, but rather a new emphasis or application of these services. Based on a recent DERC membership survey, twenty-six investigators, the majority of DERC members, indicated that confocal microscopy would enhance their research program. Since the last DERC renewal, the Central Electron Microscopy Research Facility (CEMR) has obtained a Bio-Rad MRC-600 Laser Scanning Confocal microscope equipped with a Krypton/Argon laser, Sony color printer, Sensortek Heating/Cooling Stage, Panasonic optical disk, Polaroid Freeze Frame, and Silicon Graphics Personal Iris with Vital Images VoxelView software. This instrument has been one of only two at this University. Recently, the facility acquired a new MRC 1024, capable of digital image acquisition, storage, and transfer over the Internet. Both of the instruments are available for common use. The Morphology Core Director has regularly used this equipment over the past five years and has directly interacted with the CEMR personnel in improving the confocal instrument to keep the facility at or very near state-of-the-art. With respect to the transgenic animal interests in the DERC survey, sixteen investigators expressed an interest in a morphological analysis of transgenic rats and mice. In particular, expertise is required in the analysis of embryonic lethal transgenics. The Morphology Core Director has been trained as an embryologist in graduate school and as a postdoctoral fellow at the Carnegie Institution of Washington, Department of Embryology. He has already consulted in the analysis of embryonic transgenics as well as in situ hybridization experiments carried out on embryonic mammals.